Sensor system including port body

ABSTRACT

The invention provides a device and methods for analysing body fluids wherein the device is implanted in the body and provides for both the delivery of substances into the body and for the testing of body fluids.

RELATED APPLICATIONS

[0001] This application claims the priority of German Patent ApplicationNo. 198 22 711.6, filed May 20, 1998, which is incorporated herein byreference.

BACKGROUND

[0002] The invention relates to a process and a device for accessing andanalysing body fluids. More particularly, it relates to an implantabledevice for providing access to the interior of the body and forproviding for detecting the concentration and/or existence of substancesin body fluids, wherein the device provides a vehicle for both deliveryof substances into the body and for analysing of body fluids. Theinvention encompasses various embodiments wherein the body fluids may beanalysed in situ, or partially or completely extracted or aspirated foranalysis.

[0003] A number of procedures exist in medicine for detecting theconcentration and/or existence of substances in body fluids. Whentesting for blood sugar concentration, for instance, there is the optionon the one hand of piercing the patient's skin, such as on a finger, fortesting the blood sugar content of blood drawn in this manner. Virtuallyany intercellular fluid may be examined in many different ways and fordifferent characteristics using a selected “test strip” after such afluid has been obtained. Another piercing procedure involves piercingthe skin with needles for introducing and/or retrieving a sensor at atest point in the body.

[0004] However, a severe disadvantage or drawback of such invasivetechniques is that they are generally unpleasant experiences to thepatient. Another related drawback is that a piercing may be required foreach desired test, and such piercings may be frequent and repeated. Inaddition, needle-type sensors will fail due to being affected and/orrejected by the body after a very short time (approximately half a day).

[0005] Non-invasive techniques, for instance detecting saidconcentration by fluoroscopic methods, have not yet been adequatelydeveloped to obtain sufficiently accurate values.

[0006] Port bodies, implanted subcutaneously or percutaneously and usedfor administering drugs through tubular channels, are known from atleast U.S. Pat. No. 5,306,255 and EP 0 302 076.

SUMMARY

[0007] The present invention provides an implantable device forproviding access to the interior of the body and for providing fordetecting the concentration and/or existence of substances in bodyfluids, wherein the device provides a vehicle for both delivery ofsubstances into the body and for analysing of body fluids.

[0008] It is an object of the invention to provide a method and a devicefor detecting the concentration and/or existence of substances in bodyfluids by which the disadvantages of the devices and methods describedabove are overcome as far as possible. Another object of the presentinvention is to help avoid pain and inconvenience for patients.

[0009] The invention provides a device and method for analysing bodyfluids wherein the body fluids are accessed via an access meansimplanted in the body.

[0010] The inventive method for detecting the concentration and/orexistence of substances in body fluids attains this object by accessingthe interior of the body and any fluids to be analysed by an accessmeans implanted permanently or semi-permanently in the body.

[0011] Many patients needing regular medication due to theconcentrations of certain substances in their body fluids being too lowor too high, are being administered the regular medication through animplanted, artificial access means providing access to the interior oftheir body. The process according to the invention has an object ofusing such implanted access means for gaining access to body fluids sothe fluids can be analysed. Access means, which may comprisequick-replacement elements such as a framed sealing diaphragm, may bepermanently or semipermanently implanted in the body, and includestructures or features which end at parts of the body where no blockageof the endings will occur for some length of time. Such access means maybe designed to ensure that attacks by rejection mechanisms of the bodyor attacks by body cells will not affect their function at least over apredetermined period of use. According to the present invention, theseaspects of typical access means may now also be used for accessing bodyfluids. It is an advantage of the present invention that permanent orsemi-permanent implanted access means may be used to allow access tobody fluids for analysis over an extended period of time and/or to allowfor repeated sampling or analysis of body fluids, while sparing apatient the discomfort of repeated piercings.

[0012] According to one embodiment of the present invention, access to abody fluid may be effected through a permanently or semi-permanentlyimplanted device for administering medicaments and, in a preferredembodiment, through a port body implanted in the skin, wherein the portbody comprises a tubular arrangement extending into the interior of thebody.

[0013] In one embodiment, a port body is suitable as a permanent meansof access for administering insulin, and is implanted into the umbilicalvein within the abdominal cavity of the body. The abdominal cavity, theperitoneum and the umbilical vein have proven to be advantageous sitesfor the administration of insulin, due to insulin being resorbed fasterthere than after subcutaneous administration. Owing to the fact thatinsulin consumption takes place in the body cells as such, the cellfluid also seems a suitable place to measure the blood sugar content,due to measuring a central average in this case directly at the place ofconsumption. Accordingly, port bodies according to the present inventionare suitable for the administration of insulin into the abdominal cavityand as access points to body fluid to be analysed.

[0014] Although said port bodies are invasive devices, one-timeimplantation typically will be sufficient, whereby, in a port body inaccordance with the present invention, a patient no longer mustexperience the pain and inconvenience of subsequent repeated access tobody fluids for testing purposes.

[0015] One embodiment of the process according to the invention ischaracterized by a test sensor being introduced into the interior of thebody through the access means for detecting the concentration and/orexistence of substances, with detection being performed at that point.This creates a chance for continuous and intermittent testing, wherebythe sensor remains at the test site in the interior of the body and isintroduced via a separate tube when using a port body comprising atubular system.

[0016] In another embodiment of the invention, a test sensor remainingin the interior of the body takes body fluid from the interior of thebody through the access means, followed by analysis at a point remotefrom the point of retraction. Body fluid is still analysed, forinstance, within the body, preferably at an intermediate point of thetubular system, by means of a sensor and is aspirated for this purposeto a selected point. The benefit of using an intermediate point as atest site is that any deposits, which might arise at the end of thetube, by which access may be effected, will not have any negativeinfluence on the accuracy of tests. Also, the tubular section betweenthe ends, both interior and exterior, protects a test sensor provided atan intermediate point of the tube against direct contamination. Further,constancy of temperature is ensured. When the sensor is replaced, theabdominal cavity is not affected.

[0017] According to an alternative embodiment of the process accordingto the invention, body fluids may naturally be aspirated away orextracted from the body for analysis.

[0018] In addition, a preferred embodiment of the invention uses adialysis microprobe by which substances are extracted from body fluids.

[0019] The device for detecting the concentration and/or existence ofsubstances in body fluids according to the invention comprises an accessmeans to the interior of the body, permanently or semi-permanentlyimplanted in the body, and adapted for allowing access through saidaccess means to body fluids for analysis thereof, in situ. In otherembodiments of the present invention, the body fluids may be aspiratedto a selected point with in the access means for analysis, or they maybe removed completely from the body and access means for analysis at aremote location.

[0020] Preferably, in one embodiment, the access means is a permanentlyimplanted device for administering medicaments, in particular a portbody implanted into the skin, comprising a tubular system extending intothe interior of the body. Such a port body may be implantedsubcutaneously, as well.

[0021] The access means or port body of the present invention comprisestubes, passages or pathways by means of which a test sensor may beintroduced into the interior of the body or to a selected location alongthe passages or pathways. The access means preferably comprises aseparate tube for the introduction of a sensor.

[0022] One preferred design of the device according to the invention ischaracterized in that the access means is associated with a dialysismicroprobe through which substances in body fluids are withdrawn. Themicroprobe may be either permanently or removably associated with theaccess means.

[0023] Furthermore, the invention refers to the use of an access meansto the interior of the body, permanently or semi-permanently implantedin the body, through which the concentration and/or existence ofsubstances in body fluids are detected and/or analysed.

[0024] Other objects, features, embodiments and advantages of the deviceand method of the present invention will become more fully apparent andunderstood with reference to the following description and appendeddrawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025]FIG. 1 depicts an implanted port body adapted according to thepresent invention.

DETAILED DESCRIPTION

[0026] The accompanying Figures and this description depict and describeembodiments of the port body and methods of the present invention, andfeatures and components thereof. With regard to means for fastening,mounting, attaching or connecting the components of the presentinvention to form the device as a whole, unless specifically describedotherwise, such means are intended to encompass conventional fastenerssuch as threaded connectors, snap rings, clamps such as screw clamps andthe like, rivets, toggles, pins and the like. Components may also beconnected by adhesives, glues, welding, ultrasonic welding, and frictionfitting or deformation, if appropriate. Unless specifically otherwisedisclosed or taught, materials for making components of the presentinvention may be selected from appropriate materials such as metal,metallic alloys, natural and manmade fibers, vinyls, plastics and thelike, and appropriate manufacturing or production methods includingcasting, extruding, molding and machining may be used.

[0027] Any references to front and back, right and left, top and bottomand upper and lower are intended for convenience of description, not tolimit the present invention or its components to any one positional orspacial orientation.

[0028] Referring then to FIG. 1, a port body 10, an implantable orpartially implantable device for operably coupling a conduit or hoseoutside of a human or animal body to a catheter, hose, conduit or thelike inside the body, is shown implanted in the skin 15 of a patient(human, animal, etc.). The port body 10 comprises a shaft section 11 towhich an approximately disc-shaped anchoring section 13 is attached,acting as an anchor or attachment for anchoring, attaching and/orstabilizing the port body 10 in (or under) the skin.

[0029] The shaft section 11 forms a hollow enclosure containing and/orsupporting an elastic self-closing diaphragm 12.

[0030] Separate tubes extend generally perpendicularly away from theinnermost, lower end of the port body 3, including a feed tube 23 (thefull length of which is not shown) and a shorter aspiration tube 21. Afeed catheter 24 and an aspiration catheter 22 may be introduced throughthe diaphragm 12 into each of the tubes 23 and 21, respectively.Although the tubes are shown as extending perpendicularly away from theport body 3, they may extend away therefrom at another angle. Also, insome situations, a port body may have more than two associated tubes,and the tubes 23, 21 may be adapted to contain more than one cathetereach.

[0031] The tube 23, either the mouth thereof or a point or points alongthe tube 23, is supplied with a drug, such as insulin, through the feedcatheter 24, whilst from a point or points adjacent to or at the end ofthe tube 21, e.g., at its open mouth, body fluids may be withdrawnthrough the aspiration catheter 22.

[0032]FIG. 1 shows fastening sections 14 at the top of the shaft 11,provided for connection of the upper sealing and/or closing caps of thecatheters 24 and 22, not shown in the Figure.

[0033] The feed tube 23 is preferably of a standard length of 150 or 180mm, whilst the aspiration tube 21 presumably has an approximate minimumlength of 30 mm, preferably 60 to 120 min, possibly even 180 mm. Thisarrangement therefore clearly shows that this port body may be used bothfor the supply of drugs through the feed catheter 24 and for access tobody fluids through the aspiration catheter 22. The tubes 23 and 21preferably extend into the patient's abdominal cavity where cell fluidcan be found, which may be provided with a drug or analysed for specificconcentrations.

[0034] The dashed arrows show selected various test sites for testingthe concentration or existence of certain substances. For example, asensor may be applied to test point 25 where fluid is aspired from thebottom end of the catheter 22 somewhat upwards, in order to perform atest precisely at this intermediate point 25. As described above, asensor attached at point 25 would be protected against deposits by thelower section of the tube 21 and/or the catheter 22.

[0035] When a test is performed at a point where no major deposits areto be expected, a test sensor may also be attached permanently orremovably at a point marked by the dashed arrow 26. The benefit of thisdetection method lies in the fact that aspiration is no longer requiredand detection will be feasible directly at a specified test point.

[0036] In the two embodiments described, where the test sensor remainspermanently in the tube 25 and/or on the end of the tube 26, anelectronic test sensor is used, the connecting wires of which may berouted out of the body together with the catheter 22.

[0037] Typically, electronic test sensors suitable for use in thepresent invention comprise a working electrode, a counterelectrode and azero-current reference electrode. When the shaft 11 of the port body isof a metallic material, the shaft 11 may be used as a referenceelectrode or counterelectrode, thus allowing simplification of theelectric sensor during the said tests according to the invention.

[0038] Another option for using the arrangement shown in the Figureconsists of inserting a probe (not shown) through the tube 21 forone-time testing or for each individual test. In this embodiment, theprobe may comprise a test strip for detecting a concentration. Takingand evaluation of a reading may be performed in inserted condition orafter removal.

[0039] According to the present invention, a fluid may be aspirated orremoved from the interior of the body through the catheter 22 and, asdepicted by the dashed arrow 27, analysed at a remote laboratory.

[0040] In the foregoing description embodiments of the invention havebeen presented for the purpose of illustration and description. They arenot intended to be exhaustive or to limit the invention to the preciseform disclosed. The embodiments were chosen and described to provide anillustration of the principals of the invention and its practicalapplication, and to enable one of ordinary skill in the art to utilizethe invention in various embodiments and with various modifications asare suited to the particular use contemplated. All such modificationsand variations are within the scope of the invention as determined bythe appended claims when interpreted in accordance with the breadth theyare fairly, legally, and equitably entitled.

What is claimed is:
 1. A method for analysing body fluids, in which afluid is accessed for analysis via an access means implanted in thebody.
 2. The method as set forth in claim 1, wherein access is providedvia a permanently implanted device for administering medicaments.
 3. Themethod as set forth in claim 1, wherein access is provided via a portbody implanted in the skin, including a tube arrangement extending intothe interior of the body.
 4. The method as set forth in claim 1, whereina test sensor is inserted into the interior of the body via said accessmeans for detecting the concentration and/or existence of substances. 5.The method as set forth in claim 4, wherein said test sensor remains ata test site in the interior of the body for continuous testing, saidtest sensor being inserted via said access means.
 6. The method as setforth in claim 1, wherein a body fluid is withdrawn from the interior ofthe body via said access means and analysed at a location remote fromthe point of withdrawal.
 7. The method as set forth in claim 3, whereina body fluid is analysed by means of a sensor while still in the body,preferably at an intermediate site of said tube arrangement, said bodyfluid being aspirated towards this site.
 8. The method as set forth inclaim 1, wherein a body fluid is analysed outside the body.
 9. Themethod as set forth in claim 1, wherein the body fluids containsubstances withdrawn by means of a microdialysis probe associated withsaid access means.
 10. A device for detecting the concentration and/orexistence of substances in body fluids, said device comprising an accessmeans for accessing the interior of the body, said access meansimplantable in the body and adapted to allow access to the body fluids.11. The device as set forth in claim 10, wherein said access means is apermanently implantable device for administering medicaments andcomprises a tube arrangement extending into the interior of the body.12. The device as set forth in claim 10, wherein said access meanscomprises a port body, implantable in the skin and comprising passagesthrough which a test sensor may be guided into the interior of the body.13. The device as set forth in claim 12, said port body furthercomprising a separate tube for the insertion of a test sensor.
 14. Thedevice as set forth in claim 10, said access means associated with amicrodialysis probe via which substances in the body fluid may bewithdrawn.
 15. The device as set forth in claim 10, said access meanscomprising a port body implanted in the skin of a body, and comprising ashaft section to which a generally disc-shaped anchoring section isattached, said shaft section providing a generally hollow enclosurecontaining an elastic self-closing diaphragm, a feed tube and anaspiration tube extending away from said shaft section and into aninterior region of the body, a feed catheter and an aspiration catheterreceived respectively in said feed tube and said aspiration tube.
 16. Amethod of analysing body fluids comprising the steps of: providing anport member for accessing the interior of a body, said port memberimplanted in the body; and testing body fluids via said port member. 17.The method according to claim 16, wherein the port member provides forthe delivery of substances into the body.
 18. The method according toclaim 17, wherein said port member provides for one of the partial orcomplete extraction of body fluids.